Feed means for flat warp knitting machines



Aug- 24, 1965 A. W. H. PORTER 3,201,955

FEED MEANS FOR FLAT WARP KNITTING MACHINES Filed Aug. 16, 1962 5 Sheets-Sheet 1 nvenlor A h/ Porer' Aug. 24, 1965 A. w. H. PORTER 3,201,955

FEED MEANS FOR FLAT WAR? KNITTING MACHINES Filed Aug. 16, 1952 5 SheetS-Sheet 2 ZZZ nvenlor ,4. M H. Por fer A ttorneys Aug. 24, 1965 A. w. H. PORTER 3,201,955

FEED MEANS FOR FLAT WARP KNITTING MACHINES Filed Aug. 16, 1962 5 Sheets-Sheet 3 w e Ox iff .H V i ij-! nUenlor IV /f PorzIer A ilorneys Aug. 24, 1965 A. w. H. PoRTER FEED MEANS FOR FLAT WARP KNITTING MACHINES Filed Aug. 16, 1962 5 Sheets-Sheet 4 [velo A'. 1^/ H Porzler FEED MEANS FOR FLAT WARP KNITTING MACHINES Inventor A W Porzlel" By QM Mmeys United States Patent O 3,201,955 FEED MEANS FR FLAT YNARP KNITTlNG lt/ACHNES Allan William Henry Porter, Burton-on-Trent, England, assigner to Hobourn-F.N.F. Limited, Burton-amsant, England, a British company Filed Aug. 16, i962, Ser. No. 217,444 Claims priority, application Great Britain, Aug. 16, '1961, Y 29,5%/ 61 Claims. (Cl. 65--86) Modern at warp knitting machines have one or more positively driven warp beams which are arranged to rotate at such a speed that the warp threads are unwound from the warp beam at the same rate as that at which they are consumed at the knitting points. The speed at which the warp beam is rotated must be varied as the beams are emptied to allow for the reduction of, and small fluctuations in, the diameter of the Warp threads on the beam so that the linear speed of the threads to the knitting points remains constant. The speed of rotation of the warp beam may be controlled by a warp let oit mechanism of the kind in which a sensing device is rotated at a speed depending on the linear speed of the yarn threads leaving the warp beam and this speed of rotation is compared by some form of dilterential arrangement with that of a control member that is rotated at constant speed. The sensing device may be rotated by a rotary feeler such as a roller or a belt running on the surface of the warp threads or alternatively the sensing device may be a yarn disc which is rotated either by one of the warp threads from the warp beam or by a slave thread which is wound for example one and a half times around the warp beam before being knitted with the warp threads. As the speed of the sensing device increases or decreases, there is a relative rotation between the sensing device and the control member and this relative movement is used to close one of two electrical switches which correspond respectively to an increase and a decrease in the yarn speed. Closure of one of the switches operates a mechanism which adjusts the ratio of an iniinitely variable speed gearing through which the warp beam is driven so that the linear speed of the thread returns to the required value at which the corresponding speed of rotation of the sensing device is equal to that of the control member. One example of this kind of warp letoif mechanism is described in our U.S. Patent No. 2,600,256.

The main disadvantage of this kind of system is that if the mechanism that adjusts the ratio of the gearing is sensitive enough to provide a quick correction to the warp beam speed, then there is the danger that before the appropriate switch has reopened, the system will have overcorrected and the sensing device and control member will have moved relatively to to each other in the other sense suiiiciently to close the other switch. The system will then correct and possibly overcorrect in the other direction. This leads to the production of hunting characteristics in the mechanism with consequent oscillation and chattering of the switch contacts which causes excessive wear of the parts.

According to the present invention a movement dependent on the correction of the ratio of the infinitely variable speed gearing is fed back to the two switches so that they are movedbodily in such a direction that the switch which had been closed as a result ot' relative movement between the sensing device and the control member tends to be reopened.

With this arrangement there is little danger of the system overcorrecting because the relative movement does not have to be reversed to open the switch and to prevent further correction taking place. Hunting is therefore eliminated. However, if any overcorrection does take place, the sensing device and the control member do not have to pass back through their original relative datum position before the other switch is closed because both switches and correspondingly the datum position follow the relative movements of the sensing device and the control member. The system therefore settles to an equilibrium position very quickly.

The sensing device and the control member are preferably arranged to rotate two of the parts of an epicyclic gear or the two opposite input shafts of a differential gear so that an indicating member forming a third part of the gear only moves in one direction or the other to close one of the switches when the sensing device and the control member are rotated at dilerent speeds. In order that the movement of the indicating member and the switches may be endless in either direction, they all preferably move in coaxial circles. A single correcting member which is moved in one direction or the other by an electric motor upon closure of one or other of the switches respectively may be arranged to vary both the ratio of the variable speed gearing and also to move the switches relatively to the indicating member.

One example of a flat warp knitting machine constructed in accordance with the present invention is illustrated in the accompanying drawings, in which:

FIGURE l is a diagrammatic end elevation of the machine;

FIGURE Il is a side elevation of a warp let off control box;

FGURE ill is an end view of the box as seen in the direction of the arrow lli in FIGURE Il but with the end casing removed;

FiGURE IV is a section taken on the line IV-IV in FIGURE iii;

FIGURE V is a section taken on the line V-V in FIGURE lll; and

FGURE VI is a section taken on the line VI-VI in FiGURE iV.

The machine has at each end a frame l with a bracket 2 which carries two warp beams 3 and 4. The warp sheet (not shown) from each warp beam passes over a tension bar (not shown) to the knitting point 5' where the fabric is knitted by the relative movements of the knitting elements 5a. The fabric passes from the knitting point 5 to a take-up roller 6 on which it -is wound. The end thread 7 of each warp sheet is a slave thread which passes over a bar 8, one and a half times around a yarn disc 9, over a tension bar i@ and is consumed at the knitting point 5. Each yarn disc 9 comprises two circular plates 9a, 9b, connected by rubber covered pegs 9c. The yarn is wrapped on the pegs between the circular plates. Each disc is mounted at the top of a warp let off control box 11 which is carried by the bracket 2 and controls the speed of rotation of the corresponding warp beam.

In each warp -let oi control box il the yarn disc 9 is fixed to the hollow upper input shaft l2 of a differential gear i12, and rotates on lower input shaft i3 of the differential which forms the control member and is driven at constant speed from the main driving means of the machine. This drive is through a chain i4 in which drives a sprocket on an input shaft l5. At one end the input shaft l5 is mounted in a bearing t6 and at the other end it carries a gear wheel 17 which is in constant mesh through gear 17a with another gear wheel 18 mounted on a shaft i9 that is fixed to a driving cone Z0. This cone 20 drives a Second cone 2l by means of a ring 22 and forms an innitely variable speed gearing of the type described in U.S. Patent No. 2,600,256. The ring 22 is moved between the cones 20 and Z1 by means of a ring nut 23 which is threaded onto a lead screw 24. The lead *M is 3 l.

screw'24 is rotated by means of an operating'knob 25 2.1 is fixed to a shaft V29 carrying a gear Wheel lwhi'chis i in constant mesh with another gear wheel31 through an l idler gear 32. The shafts 19 and 29 are parallel to the'y shaft 15, as best seen in FIG. VI. The gear wheel V31 is carried byv a shaftV 32a which also carries a worm 33 that f meshesr with a worm wheel.-34 on the bottom' ofthe input shaft 13. By rotating the operating knob25 and altering the position' of the ring 22 the ratiojof the drive. between thev cones and 21 may be altered in dependence upon the required warprlet-off speed and the diameterfof the..

warp beam. The inputrshaft 13 of the differential is therefore'rotated at a constant speed which has been `cor-` requirements.

the other.' This willrmove the ring nut 50 and hence the ring 51 in one direction or the otherfbetween the cones Z1 and 52. j The ratio. of the gearing in the drive to the output shaft 62 is therefore varied. l f When the -indiaereflbf37 019865-01@ ofthe pairs vof wiping contacts 38and'39 the resulting rotation of the leadrscrew 49 will cause the worm wheel A64. and hence the cage'liiba to rotate in such a direction that the pair of wiping contacts which have been closed tend to move away fromethefindicating member 37 so that theyare opened gonce more.V k'If the correction in the speed of rotation .ofthe warp beam is insufficient the indicating member 37 willfollow. ther'otation yofthe cage 40a. until the necessary variationin .the ratioof the drive between the The yarnbdisc 9 is rotated'by-'the slaveV threadY and drives the upper input shaft .12 Vandgthrough it the upper input gear of the differential at a .speed which is yproportional to the linear speed of thewarp sheet leaving the corresponding warp beam and.this speed of rotation is compared with the rotationalspeed of the lower input member 13 .in the differential lower input gear splined thereto. When the yarn disc and the lower input member 13 are rotated at the same speed planetary pinionss' and 36, which are engaged between said upper and lower gears in the differential, rotate about their common axis u but do not rotate about the axis of the shaft 13. The planeta'rypinion 36 carries a projecting indicating member 37 between two pairs of electrical wiping contacts'iV and 39 which are carriedby the cage 4&1 ofthe differential. These pairs of contactsare separated by 15. around the circumference .of the cage 40a. .The .two pairs of contacts 33 and 39 are connected one to each of two solenoids 40 and 41 respectively. The .operation of one of the switches causes a clutch'member 42 which is cones21 lar'1d'52 has been accomplished.y In the event of over correction Vthe indicating' member V37 will quickly 20. ing member. Any variation in theV ratio of the drive between the' cones21 and 52 ips-therefore Vfed backl to the Cage 46a and Vthe system quickly settles toa new equi-A librium in whichihe yarndisc 9 is rotatedby the slave thread at the same speed as the input shaft 13 is rotated. 1 1 One complete revolution-of the cage 4th: is equivalent tothe full traverse of the ring 51 between the ends of the cones 21 and152. i

lclaim: y

1. In a flat warp knitting machine' ofthe k-ind having a Warp beam, powermeans .for Vdriving saidwarp beam, infinitely variable speed gearing operatively interposed between said power means and Vsaid warp beam, and a warp vlet-off Amechanism controlling 'said infinitely variable t speed gearing whereby saidwarp .,beamris rotated at a splined to the input shaft 13 to be movedy upwards by a y selector fork,v(not shown)v into engagement with a bevel gear wheel 43 and closure ofthe other switchk causes the clutch member to move downwards into' engagement with a bevelY gear :wheel 4.4. These two bevel gear wheels 43 and-44 are in constantmeshinrdiametrically opposite 'Y positions with another bevel gear wheel45 and are freely. f

rotatable on the shaft 13. The gear wheel 45 is xedfto a shaft 46 which carries a pinion 47 in constant mesh vwith another pinion'48 on a second leads'crew 49. This lead vspeed such thatthe linearnspeed' of yth read leaving the peripheryof saidwrarp beam is maintained,substantially .constant at a desired value; theimproved warp let-off mechanism comprises, aV Vrotaryy sensing device adapted lto krotate ata speed corresponding Vto the linear speed of thread leaving the periphery of. said Y warp beam,a rotary Y Vmember adaptedrtorbe yrotated at a constant speed corresponding to the 'desired linear speed of threadleaving saidwarp beam, movable actuating .means respective to relativerotationrbetweenjsaid sensing device and said rotaryrimember, first'switch .means positionedto be closed transmits drive between the secondk conelglY and a'third cone 52, This third cone` 52 is fixed to a shaft Y53.which carries a gear wheel 54 in constant mesh'witha gear uponmovementiof said 'actuatingmeans in onedirection followingr 'relative' rotation; between said sensing device and said sensing device andsaid rotary member in one sense` and connected, when closed, to cause the ratio of wheel 55 on a shaft 56. This shaft`56 .carries aY bevel .l

gear wheel` 5,7 in constant mesh with another bevel [gear` 58 on a vertical shaft 59 carrying a worm 60.' The worm 60 is in mesh with a worm wheel 61 on an output shaft 62 which rotates the corresponding warp beam; The

lead screw 49 is al'sopro'led with a worm .63 which" drives a worm wheel, 64 connected tothe bottom of 4.the

c age 40a ofthe differential.

the yarn disc and hence the inputshaft 12v of the differ-Y ential are rotated at a different speedfthan the otheriinput This ,causes the planetary` v pinion 36 to move'around the axis of the shaft Y13A until shaft 13 'of vthe differential.

the indicating member 37 closesbone of thezpairs .of Ywip-v ing contacts Y38 and 39,v This causes solenoid 40. or 41 to be operated and link consequencethe clutch member 42'is moved Vupwards or Vdownwards into engagementV with one Yof the bevel gear wheels 43 and 44. Depending 43- and 44. Depending. on which'ofY the'bevel gear l said infinitely'variable `speed .gearingA to bek increased, s ecpndlswitch meanspositioned to .be closed upon movement 'fof said 'actuating means in the .other direction fol- Ilowing,relative rotation between said sensing device and said rotary memberrin the `other sense and connected, when closed,to cause the ratio .of said infinitely variable speed gearing to be decreased, means for moving said switchmeans'bodily toward and away from saidvactuating means, and feed back means adapted to transmit back 1 to said switch movingmeans a movement dependent on Upon variation in the linear speed of the slave threadu` asta result of relative rotation between said sensing'device n, e .and said rotary member is moved awayfrom said actuatthercorrectionto the ratio o f saidinfinitely variable speed gearing wherebyfa vswitch means which has` been closed ing means and reopens.

vhas a rst toothed .gear'rotatable with said sensing device,

a secondrtothed `gear rotatable with .said rotary member,

Vand saidactuator.A means includes .a part which meshes with saidfirst and Asaidfsecondl toothed gears. b

S. The inventionnacording to claim VLgvvherein said feed baclrn'eans comprises a vsingle correcting member A 'and'an-electric frnotor. adapted to move said correcting wheels 43 and-44is rotated :the shaft 46 .andhence thei i lead screw 49 Vwill be rotated in either one direction orv 'e member in one direction'upon closure of said rst switch means andV tomove said Vcorrecting member inthe other direction upon closure of saidsecondswitch means, said correcting member being adapted both to vary the ratio of said infinitely variable speed gearing and to move said first and second switch means relatively to said actuating means.

4. A at warp knitting machine according to claim 1, comprising rst and second inlinitely variable cone drives interposed in series between said power means and said warp beam, said rst cone drive being adapted to be set to a ratio corresponding to the required warp let-off speed and to the beam diameter and said second cone drive 10 through said rst cone drive, said rotary member of said warp let-01T mechanism being driven at said constant speed by the second cone of said rst cone drive.

References Cited by the Examiner UNTED STATES PATENTS 2,541,192 2/51 Blake 66--86 2,598,540 5/52 Henry 66-86 2,600,256 6/52 Morrison et al. 66--86 DONALD W. PARKER, Primary Examiner.

RUSSELL C. MADER, Examiner. 

1. I A FLAT WARP KNITTING MACHINE OF THE KIND HAVING A WARP BEAM, POWER MEANS FOR DRIVING SAID WARP BEAM, INFINITELY VARIABLE SPEED GEARING OPERATIVELY INTERPOSED BETWEEN SAID POWER MEANS AND SAID WARP BEAM, AND A WARP LET-OFF MECHANISM CONTROLLING SAID INFINITELY VARIABLE SPEED GEARING WHEREBY SAID WARP BEAM IS ROTATED AT A SPEED SUCH THAT THE LINEAR SPEED IS THREAD LEAVING THE PERIPHERY OF SAID WARP BEAM IS MAINTAINED SUBSTANTIALLY CONSTANT AT A DESIRED VALUE; THE IMPROVED WARL LET-OFF MECHANISM COMPRISES, A ROTARY SENSING DEVICE ADAPTED TO ROTATE AT A SPEED CORRESPONDING TO THE LINEAR SPEED OF THREAD LEAVING THE PERIPHERY OF SAID WARP BEAM, A ROTARY MEMBER ADAPTED TO BE ROTATED AT A CONSTANT SPEED CORESPONDING TO THE DESIRED LINEAR SPEED OF THREAD LEAVING SAID WARP BEAM, MOVABLE ACTUATING MEANS RESPECTIVE TO RELATIVE ROTATION BETWEEN SAID SENSING DEVICE AND SAID ROTARY MEMBER, FIRST SWITCH MEANS POITIONED TO BE CLOSED UPON MOVEMENT OF SAID ACTUATING MEANS IN ONE DIRECTION FOLLOWING RELATIVE ROTATION BETWEEN SAID SENSING DEVICE AND SAID SENSING DEVICE AND SAID ROTARY MEMBER IN ONE SENSE AND CONNECTED, WHEN CLOSED, TO CAUSE THE RATIO OF SAID INFINITELY VARIABLE SPEED GEARING TO BE INCREASED, SECOND SWITCH MEANS POSITIONED TO BE CLOSED UPON MOVEMENT OF SAID ACTUATING MEANS IN THE OTHER DIRECTION FOL- 